Identification of Potential Brackish Groundwater Production Areas – Trinity Aquifer

Project Summary:

This project is designed to evaluate the fresh-, brackish-, and saline-groundwater resources of the Trinity Aquifer. The technical approach will result in a reliable and defensible resource characterization for supporting water resources planning in GMAs 8, 9, and 10. The study has the following guidelines and objectives:

  1. Delineate fresh, brackish, and saline groundwater both vertically and horizontally in the aquifers of the project area.
  2. Use the groundwater salinity classification developed by the U.S. Geological Survey (Winslow and Kister, 1956) to categorize the water delineated. The classification is based on the concentration of total dissolved solids (milligrams per liter) in water and includes the following: fresh (0 to 1,000); slightly saline (1,000 to 3,000); moderately saline (3,000 to 10,000); and very saline (10,000 to 35,000)./li>
  3. Quantify the volume of available fresh, brackish, and saline groundwater.
  4. Delineate potential production areas that are separated by hydrogeologic barriers sufficient to prevent significant impacts to water availability or water quality in any part of the same or other fresh water aquifers.

During the course of the study the team will perform a thorough search through publicly available databases to identify potentially valuable information for additional analysis of the stratigraphy, lithology, and water quality in GMAs 8, 9, and 10. Published or documented data will be used. Key sources of data are water chemistry studies, well logs, geophysical logs, and hydrogeological studies. Data sources include the TWDB BRACS and Groundwater databases, the Railroad Commission of Texas (RRC) Q-log database, and the Bureau log library. Data sources also include U.S. Geological Survey topographic data (including digital elevation models), published geologic maps, published fault maps, stratigraphic measured sections, stratigraphic fence diagrams, cross sections, thicknesses, and well data.

Stakeholders will be invited to participate in a meeting where a presentation and discussion of Potential Production Areas will be made. This input will be important in the prioritization of areas for production.

A final report will summarize the data collection and evaluation, model conceptualization and hydraulic analysis, volume calculation tools, sensitivity analysis, and potential production zone delineation. All source data will be delivered as part of the final brackish water production zone report (delivered in both Microsoft Word and PDF formats).

TWDB Contract Manager:
Mark Robinson, P.G.
Funding Recipient:
Southwest Research Institute
Project Administrator:
Ron Green, Southwest Research Institute
Project Start Date:
January 6, 2016
Project Completion Date:
August 31, 2017
Total Project Cost:
TWDB Share of Project Cost:
The study will develop data and a report that will be available to researchers and decision-makers to assist in the site selection of future groundwater desalination and aquifer storage and recovery projects.

Project Details


Project Sponsors:

Texas Water Development Board
Mark Robinson, P.G. - Contract Manager
1700 N. Congress Avenue
Austin, TX 78711

Funding Recipient:

Southwest Research Institute
6220 Culebra Road
San Antonio, TX 78238

Project Manager:

Ronald T. Green, Ph.D., P.G.
Southwest Research Institute
6220 Culebra Road
P.O. Box 28510
San Antonio, TX 78238

Project Milestones

Event Date
Announcement of Request for Proposals in Texas Register November 10, 2015
Initial Statement of Interest received by TWDB November 24, 2015
Study approved by TWDB Board January 6, 2016
Contract executed April 4, 2016

Progress Reports

Stakeholder Meetings

Draft Final Report

Final Report

  • The final report has not yet been produced.